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Original Research

Efflux Pumps Contribute to Intrinsic Clarithromycin Resistance in Clinical, Mycobacterium abscessus Isolates

, , , , , , , & show all
Pages 447-454 | Published online: 12 Feb 2020

Figures & data

Table 1 MIC of Clarithromycin for 194 Clinical M. abscessus Isolates

Table 2 Blast Search of the M. abscessus Genome with Reference Gene Sequences Corresponding to Efflux Pumps Conferring or Putatively Involved in CLA Resistance

Figure 1 Efflux pump gene expression by clinical, M. abscessus isolates following exposure to CLA stress. Isolates that were CLA-susceptible, -intermediate and resistant [without (unexplained) or with a rrl 2270/2271 mutation] are shown. MAB_2355c (A), MAB_1409c (B), MAB_1846 (C) and whiB7 (D), message levels were quantified by qRT-PCR. Open circles, triangles, diamonds, and solid circles indicate the distribution of mRNA expression levels in isolates comprising the sensitive, intermediate, unexplained drug resistance, and rrl 2270/2271 mutation groups, respectively. Experiments were repeated >3 times for each isolate; error bars represent the standard error of the mean for each data set.

Figure 1 Efflux pump gene expression by clinical, M. abscessus isolates following exposure to CLA stress. Isolates that were CLA-susceptible, -intermediate and resistant [without (unexplained) or with a rrl 2270/2271 mutation] are shown. MAB_2355c (A), MAB_1409c (B), MAB_1846 (C) and whiB7 (D), message levels were quantified by qRT-PCR. Open circles, triangles, diamonds, and solid circles indicate the distribution of mRNA expression levels in isolates comprising the sensitive, intermediate, unexplained drug resistance, and rrl 2270/2271 mutation groups, respectively. Experiments were repeated >3 times for each isolate; error bars represent the standard error of the mean for each data set.

Table 3 Efflux Pump Inhibition Decreases the MIC of Clarithromycin for Non-Susceptible Isolatesa